1. Field of the Invention
This invention relates to a storage bin structure for superposed articles in an automatic vending machine, more particularly to a storage bin structure in which it is easy to vary the length of the storage space for the articles and to move the articles.
2. Description of the Related Art
The improvement of this invention is directed to a conventional storage bin structure for superposed articles to be sold in an automatic vending machine, which is shown in FIGS. 1, 2 and 3. As illustrated, the conventional storage bin structure consists of a wall assembly 1 and a conveyer unit 2. The wall assembly 1 includes an upright support plate (D), two side wall units 11, 12, a front wall unit 13, a top wall unit 14, a bottom wall unit 15, and a rear wall unit 16. The support plate (D) is fixed in the machine and has two horizontal rows of holes (D1) so as to screw the side wall units 11, 12, the top wall unit 14 and the bottom wall unit 15 thereto. The front wall unit 13 is screwed to the side wall units 11, 12. The top wall unit 14 and the bottom wall unit 15 have lengthwise slide slots 141, 151 formed therethrough so as to connect slidably the rear wall unit 16 thereto. The rear wall unit 16 is locked on the top wall unit 14 and the bottom wall unit 15 by lock bolts. Another horizontal row of holes (D2) is formed through the support plate (D) so that the conveyer unit 2 is screwed thereto. The conveyer unit 2 includes a conveyer body 21 attached to the support plate (D), a motor 22 activating a gearing 23, a rotating shaft 24 driven by the gearing 23, two front wheels 24 sleeved rigidly on the two ends of the rotating shaft 24, two rear wheels 26 mounted rotatably on the conveyer body 21, and two endless belts 27 running around the front wheels 24 and the rear wheels 26 so as to transfer the rotation of the front wheels 24 to the rear wheels 26. The bottom wall unit 15 is positioned between the conveyer belts 27, thereby permitting the superposed articles (A1) to be supported on the belts 27. The side wall units 11, 12 define a storage space therebetween in which the articles (A1) are placed. If necessary, the rear wall unit 16 can be moved forward or backward to a suitable position in which the distance between the front wall unit 13 and the rear wall unit 16 is slightly greater than the length of the articles (A1). In this way, the superposed articles (A1) can be arranged in a tier. The front wheels 24 are at a level slightly higher than that of the rear wheels 26, so as to prevent the lowermost article (A1) from unwanted forward movement. Entry of coin or coins activates the motor, thus driving the belts 27 to move the lowermost article (A1) forward away from the storage space. The conventional storage bin structure suffers from the following disadvantages:
(1) Because the rear wall unit 16 is positioned behind the articles (A1), it is difficult to adjust the position of the rear wall unit 16.
(2) When the articles (A1) are too heavy, the power of the motor cannot activate the belts 27, due to the fact that the front wheels 24 are at a level higher than that of the rear wheels 26.